The Chapter Introduction Tells the Story of the Journeys of Robert

The chapter introduction tells the story of the journeys of Robert Ferguson and T. S. Hudson to make the point that

A) America underwent a transportation and industrial transformation between the 1860s and 1880s.
B) the railroad was America's first big business.
C) travel in the United States was difficult and crude by twentieth-century standards, but Americans loved to travel anyway.
D) few foreigners toured the United States before 1900.